She will most probably take right to them but they will be afraid and run. I always introduce new babies in the dark...it just works better. But ducks can be contrary. Use a small confined space where the babies cannot hurt themselves trying to get away from the duck. Keep an eye on her for a while to make sure that she does not become agressive. How old are the ducklings? That will make a difference, as she will want to mother little ones faster then older ones.